Ok so I am a 34 waist I fit into the 44 and the top and bottom fit great. I went to the store and got to try it on and it fits perfectly so for guys I am a 34-30 so it looks like sizing up 10 for me. Hope it helps out

Suit was for husband for Halloween party & work. He is tall & thin. Usually wears pants in a 36. We got suit in a 38 just in case. Sent it back & got the 42. So I don't know how the sizes are determined, but DEFINITELY GO UP IN SIZE